Sam raised his eyebrows at her. "Everything? How long do you have? There's kind of a lot to tell." He smiled ruefully. He hated talking about his past, or his future as the case may be now, basically talking about his life in general was a source of discomfort for him but he couldn't shoulder this himself and there was no one else he could, or would want to, tell.
"I guess the key points for this current situation are that Dean has a curse on him, an ancient curse that allows him to use a powerful weapon called the first blade. He needed it to kill an enemy of ours that otherwise couldn't be killed, but it changed him. The point in our reality that I came from.....he was dead, only...apparently he wasn't. The curse wouldn't let him die so it brought him back to life.....as a demon." Sam stopped, searching her face for any sign he should stop talking. When he received no protest he went on. "I cured him, but the curse is still changing him even now. It makes him angry and violent....bloodthirsty. It's only a matter of time before it turns him again. So from what I can gather I've been looking for ways to cure him, Charlie was...well the details are kinda fuzzy because I only saw a little but from what I worked out she had found a way she thought would work to fix Dean, but someone else wanted it and she wouldn't tell them so they killed her. But all this was happening without Dean knowing." Sam looked down at his hands. "She was like a sister to us.... Especially him. If she died because of me he'll never forgive me." Sam knew this for a fact because if it was true then he could never forgive himself.